Despite the acknowledged benefits of crop diversification, the transition towards more diversified cropping systems needs to be supported, mainly due to socio-technical lock-ins favoring major dominant crop species. This calls for the development of new approaches to support the design of locally tailored diversified cropping systems. This paper aims to present an original participatory and multi-actor design approach, developed to support the introduction of camelina (Camelina sativa) into the cropping systems of northern France and to provide some insights about the characteristics, the specificities, and the limits of this approach to support its use and adaptation to other contexts. For 3 years, and in connection with the development of an oilseed biorefinery, we gathered a variety of actors (farmers, advisors, engineers in agronomy, researchers, and industrialists) to locally support the introduction of camelina in the cropping systems. First, we illustrate the diversity of the modalities that have been collectively imagined to introduce and manage camelina in the local cropping systems. Then, we describe the originality and the diversity of the knowledge produced on camelina, especially during the assessment of some of these modalities within on-farm experiments. Finally, drawing on concepts and theories from design sciences, we show that (i) the pre-existence of networks of actors, (ii) the rationale involvement of the actors, (iii) the implementation of a situated design process fueled by action and distributed among actors, (iv) the sharing and the circulation of knowledge among a diversity of actors involved in the production and use of the new crop, and (v) the implementation of an effective network management contributed to foster the three key elements that we identified as crucial to support crop diversification, namely, the production of actionable knowledge, the exploration of new ideas/concepts, and the active participation of a diversity of actors of the agri-food system.